1. Field of the Invention
This invention relates to illumination devices comprising light emitting diodes (LEDs), and also keypads that can selectively control zone, scene and show illumination among the LED illumination devices arranged among a structure based on changes to correlated color temperature (CCT) as a function of different dimcurves and brightnesses.
2. Description of the Relevant Art
The following descriptions and examples are provided as background only and are intended to reveal information that is believed to be of possible relevance to the present invention. No admission is necessarily intended, or should be construed, that any of the following information constitutes prior art impacting the patentable character of the subject matter claimed herein.
Illumination devices, sometimes referred to as lighting fixtures, luminaries or lamps include incandescent illumination devices, fluorescent illumination devices and the increasingly popular LED illumination devices. LED illumination devices provide a number of advantages over traditional illumination devices, such as incandescent and fluorescent lighting fixtures. LED illumination devices have lower power consumption, longer lifetime, are constructed of minimal hazardous materials, and can be color tuned for different applications. For example, LED illumination devices provide an opportunity to adjust the chromaticity from red, to blue, to green, etc., or the correlated color temperature (alternatively referred to simply as “color temperature”), from warm white, to cool white, etc.
An LED illumination device can combine a number of differently colored emission LEDs into a single package. An example of a multi-color LED illumination device is one in which two or more different chromaticity of LEDs are combined within the same package to produce white or near-white light. There are many different types of white light LED illumination devices on the market, some of which combine red, green and blue (RGB) LEDs, red, green, blue and yellow (RGBY) LEDs, phosphor-converted white and red (WR) LEDs, RGBW LEDs, etc. By combining different chromaticity colors of LEDs within the same package, and driving the differently colored LEDs coated with or made of different semiconductor material, and with different drive currents, these illumination devices can mix their chromaticity output and thereby generate white or near-white light within a wide gamut of CCTs (color temperatures) ranging from warm white (e.g., 2600K-3700K), to neutral white (e.g., 3700K-5000K) to cool white (e.g., 5000K-6000K, or daylight (e.g., 6000K-8300K). Some multi-colored LED illumination devices also enable the brightness of the LED illumination device to be changed to a particular set point. These tunable LED illumination devices should all produce the same color and color rendering index (CRI) when set to a particular brightness and chromaticity on a standardized chromaticity diagram.
A chromaticity diagram maps the gamut of colors the human eye can perceive in terms of chromaticity coordinates and spectral wavelengths. The spectral wavelengths of all saturated colors are distributed around the edge of an outlined space (called the “gamut” of human vision), which encompasses all of the hues perceived by the human eye. In the 1931 CIE Chromaticity diagram shown in FIG. 1, colors within the gamut 10 of human vision are mapped in terms of x/y chromaticity coordinates. The chromaticity coordinates, or color points, that lie along the blackbody locus, or curve, 12 obey Planck's equation, E(λ)=Aλ−5/(e(B/T)−1). Color points that lie on or near the blackbody curve 12 provide a range of white or near-white light with color temperatures ranging between approximately 2000K and 10,000K. These color temperatures are typically achieved by mixing light from two or more differently colored LEDs within the LED illumination device. For example, light emitted from RGB LEDs may be mixed to produce a substantially white light with a color temperature in the range of about 2300K to about 6000K. Although an illumination device is typically configured to produce a range of white or near-white color temperatures arranged along the blackbody curve 12 (e.g., about 2300K to 6000K), some illumination devices may be configured to produce any color within the color gamut triangle formed by the individual LEDs.
At least part of the blackbody curve 12 is oftentimes referred to as the “daytime locus” corresponding to the Kelvin scale of color temperatures of daytime. When implementing the daytime locus, it is desirable to emulate daytime color temperatures. Proper daytime emulation requires that target color temperatures increase after sunrise to noon local time, and thereafter decrease after noon to sunset. It is further desirable that the LED illumination devices arranged in various zones throughout the structure can thereafter appear as having the same target color temperature as that of the natural changes in the sun orientation to that structure. If emulation is needed for more than one zone, then one or more zones can be grouped into a scene. A scene is therefore made up of an illumination output from a group of LED illumination devices arranged throughout a structure as one or more zones. It is desirable that either the LED illumination devices within a zone or within one or more zones of a scene have the same illumination output at a particular time. Thus a scene containing a plurality of LED illumination devices desirably has the same brightness and color temperature at a particular moment in time and thus is static for that particular scene. By its nature, a scene is static in terms of the illumination output (color temperature and brightness) for a period of time. Changing from one static scene to another scene to form different illumination outputs among a plurality of illumination devices within one or more zones forms what is known as a show. There may be other LED illumination devices within another scene throughout the structure that can have a different brightness and/or color temperature. For example the illumination devices within a first scene can have a first brightness and/or color temperature, and the illumination devices within a second scene can have a second brightness and/or color temperature. The first scene can be a first illumination output from among a first group of illumination devices, whereas the second scene can be a second illumination output from among the same group of illumination devices, or from a different group of illumination devices.
It would be desirable to control each scene throughout the structure with a keypad. Buttons on the keypad can be dedicated to change the brightness and/or color temperature of a grouped scene of LED illumination devices. By depressing possibly a single button, the brightness and/or color temperature of a grouped plurality of illumination devices that form a scene can change from a first static illumination output to a second static illumination output until such time as the button is depressed again to make further illumination output changes.
It would also be desirable to automatically change at various times of day the static illumination output of the grouped scene of LED illumination devices. The change can occur by depressing buttons on the keypad at various times of day to change from one static output to another, or the change can occur automatically and at pre-defined, periodic intervals without any user intervention. The automatic, periodic changes to the illumination output of a grouped scene of LED illumination devices to another illumination output of the grouped scene forms a show. It would be desirable to map the different brightness and/or color temperature outputs from the grouped scene of LED illumination devices on a dimcurve, and to periodically change at least a portion of the dimcurve using buttons on the keypad. As a dimcurve changes from, for example, a first dimcurve to a second dimcurve, the grouped scene of LED illumination devices can change from one show along the first dimcurve to another show along the second dimcurve.
Although the term “scene” references at least one zone containing a plurality of LED illumination devices, scene hereinafter also references the illumination output from the at least one zone and that output comprises a brightness and color temperature from the at least one zone at a particular point in time and that extends for a period of time until another scene having a different illumination output is produced. Thus, a series of scenes along a dimcurve, each possibly having different brightness and color temperature values, comprise the dynamically changing scenes that form a show. A scene therefore represents not only one or more zones, but also a static brightness and color temperature output from the zones that, when automatically changed throughout the day, forms a show.
It is desirable that the target color temperatures needed to emulate the natural changes in the sun orientation to a structure containing LED illumination devices change not only as a function of brightness but also as a function of the time of day. The changes in color temperatures as a function of brightness and time of day form different dimcurves that at emulated sunrise, for example, the LED illumination devices can produce 2300-2700K predominant emulated red with some yellow sunrise sky, at noontime 5000-6500K predominant emulated blue noontime sky, and again at 2300-2700 predominant emulated red sunset sky—similar to the differences between warm white, daytime/cool white, and back to warm white.
A need therefore exists in grouping LED illumination devices within one or more zones of a structure to form a scene, and to statically change the illumination output of the LED illumination devices of that grouped scene of illumination devices from one scene illumination output to another (i.e., from a first brightness and/or first color temperature of a first scene of the grouped scene of LED illumination devices to a second brightness and/or second color temperature of a second scene of the same grouped scene of LED illumination devices). A need also exists in forming a series of scenes (albeit the same plurality of LED illumination devices within the scene but with different brightness and/or color temperatures) along a dimcurve and to dynamically change the brightness and color temperature illumination output along the dimcurve to create a new dimcurve, and to map the color temperature and brightness values of the series of scenes for each dimcurve. A scene can be assigned to a particular time of day along a given dimcurve, with other scenes having different color temperature and brightness values assigned to other times of day. A further need exists for assigning the scenes, each having a mapped color temperature and brightness value, to various times of day to form a show. If the mapping is performed so that the color temperature emulates the daytime locus, the desired show becomes a natural show that will automatically change the color temperature output of the LED illumination devices within a scene at a particular time of day, and among a series of scenes throughout the day, along a dimcurve that relates to the daytime locus. A need further exists to control changes to color temperature output from a zone or a scene, and to control the natural show by momentarily, permanently or persistently changing, in a smooth and non-disjointed fashion, the natural show among scenes a various times of day using one or more buttons on a single keypad, such as a global keypad.